by: Sergio Jaramillo, Sid Richardson ’10
Most innovative scientific ideas initially face vehement opposition, followed by a gradual process of testing and evolving into a universally accepted dogma. Religion and politics — and their delineation of ethics and morality — have historically played a large role in the scientific process, and in bioethics today, they continue to assume a large role in morally controversial topics, one of the most prominent of which is embryonic stem cell research. The current Embryonic Stem Cell (ESC) revolution was ignited by Dr. James A. Thompson at the University of Wisconsin in 1998. The call to explore stem cells’ potential to regenerate tissues and more effectively treat Parkinson’s, Alzheimer’s, among many other diseases, has sparked a great deal of political and ethical controversy. Due to the debate over the ethics of using fertilized embryos in stem cell research, this issue has also led to groundbreaking findings on the possibility of using other kinds of cells to derive the same benefits.
The isolation of the Human ESC was a great scientific achievement with an even greater therapeutic potential. An embryonic stem cell is defined as a stem cell derived from the inner cell mass at the blastocyst stage of a fertilized oocyte. The cells are considered pluripotent, because they posses the capacity to divide and produce cells derived from the three germ layers (ectoderm, endoderm, and mesoderm). However, ESCs are limited in their inability to differentiate into the trophoblasts, which give rise to the placenta. Scientists believe that one day damaged tissue will be regenerated by those “shimmering spheres of human potential” (National Geographic, July 2006) to spark a renaissance of life in damaged tissue.1 However, there are risks: if ESCs are left undifferentiated in the body, they can differentiate uncontrollably, causing a Teratoma, a benign tumor. On the other hand, ESCs may offer a cure for Parkinson’s, Alzheimer’s, Diabetes, cancer, Hemophilia, and many other diseases.
In light of the fact that ESCs have been the center of much controversy, useful insight may be gained through studying the history of religions and secular debate on the beginning of life. In scientific terms, an embryo is defined as the stage when the dividing cells in the recently-fertilized egg gain control of their cellular machinery by beginning to produce their own enzymes; this stage occurs in the cleaving cell one to two days after conception. The current Roman Catholic Church’s stand on the human status of the blastocyst is that “the ablation of the inner cell mass (ICM) of the blastocyst, which critically and irredeemably damages the human embryo, curtailing its development, is gravely immoral and consequently is gravely illicit”.2 However, this has not always been the stand of the Roman Catholic Church; until the twelfth century it believed in Saint Augustine’s doctrine of “the quickening” that stated the embryo acquires humanhood through the acquisition of sentience. From the twelfth century to 1869, the Church believed in Saint Thomas Aquinas’s doctrine of “delayed hominization,” which stated that of the vegetative, animal, and rational stages, the last stage must be reached for embryo to fully attain humanhood. In 1869, Pope Pius IX decreed the beginning of life at the moment of conception due to knowledge that fertilization involved sperm and eggs. Thus, for nearly 2,000 years The Church had accepted the doctrine of “late humanhood” in one form or another, and the new cannon has been in place for about 150 years. Just as the Roman Catholic Church has not been a picture of unwavering conviction on the status of life and its beginning, neither have other faiths such as Islam, Judaism, and protestant branches of Christianity in which religious and secular scholars are split on this issue.
Some regard ESC research as tantamount to abortion, claiming that the blastocyst is being destroyed. According to Anne Kiessling, a stem cell researcher, the irony of the situation is that when opponents of research on fertilized eggs and early embryonic development try to stop such research, they actually inhibit the scientific understanding of the process. This in turn impedes the development of new ways to prevent pregnancy, perpetuating the need for abortion itself.2 Many proponents of ESC research find that conferring humanhood to the original blastocyst is problematic because until it has reached the morula stage (14th day blastocyst), the blastocyst has the potential to split, forming twins. On this basis, they reason that it is at least counterintuitive for a person to split in two, so one cannot confer humanhood until the potential for a unique human is actually manifested in the embryo through a propensity to acquire a unique biological personality. Whether or not ESC research implies terminating life, one thing is certain: there are hundreds of thousands of frozen blastocysts in fertility clinics around the world destined to be destroyed.
Because of the ethical controversies regarding the use of fertilized embryos for the isolation of embryonic stem cells, scientists looked for a way to turn a somatic (or body) cell into a human ESC. In theory, all somatic cells in the body are the same because they contain the same number of chromosomes. The amount of gene expression guides the differentiation of cells along commitment pathways to their lineages: from embryonic to adult stem cells and then to somatic cells. In other words, genes are upregulated and downregulated in different sequences, with varying levels yielding a cell type. Therefore, it is theoretically possible to take a fibroblast (skin) cell and turn it into a pluripotent cell by inducing the expression of the necessary factors that match with the expression profile of ESC. The induction of pluripotency on fibroblasts was first performed in mice by two different research groups, creating high expectations for the possibility of reproducing the work with human fibroblasts. Then, on November 11, 2007, the research journals Cell and Science each published an article on the induction of pluripotency on human fibroblasts by two different independent research groups. This news made the headlines across the world as a monumental achievement in ESC research. Some scientists in the embryonic stem cell research community insist that this breakthrough is far from a replacement to embryonic stem cell research, and that the methods to induce pluripotency are problematic for therapeutic application in human beings.
Despite the controversies, it is indisputable that there lies a great potential in stem cell research to cure a myriad of diseases. The new research on fibroblasts is part of a strong social and scientific movement to make such treatments possible, and perhaps it marks a beginning of the end to the ethical controversy.
References
1. Rick Weiss. Stem Cells, The Power to Divide. National Geographic Magazine. July 2005.
2. Kiessling, A., Anderson, S.C. Human Embryonic Stem Cells (second edition). Jones & Bartlett: October 31, 2006.